TFM_TOPINS questions

[james]

Hi
 
During my ongoing efforts to migrate a model over to VEDA2, I'm trying to understand the processing order and requirements for TFM_TOPINS in VEDA-FE. We use such a table to map a set of biomass commodities as alternative inputs to various processes (e.g. bio kerosene into any processes that can take kerosene for instance) and I’m trying to understand some issues (VEDA2 and VFE seems to behave differently). For VFE, my questions:
 
1) If a TOPINS table is in the BY_Trans do the commodities it maps need to be already defined in the VT workbooks? And in all the regions that the VT workbooks cover (assuming separate workbooks per region).
 
2) If a new commodity is defined in a SubRES file (that isn’t in the VT workbooks), where should the TOPINS table be placed in order to correctly map that commodity?
 
3) With a TOPINS defined in a SubRES Trans or Scenario file VFE doesn't seem to pick up the additional commodity input options for a process in a user constraint (despite the user constraint being ordered after the TOPINS). What am I doing wrong?

Thanks!

[AKanudia]

Tags are processed as they are read in VEDA_FE. In Veda2.0, all tag tables are read right upfront, and then processed in a sequence that is similar to what is followed in VEDA_FE. Answers to your specific questions:

1. TOPINS tables in BY_Trans will see only those commodity-region combinations that are defined in SysSettings or one of the BY workbooks.
2. For commodities defined only in a SubRES, the TOPINS table has to be either in the Trans file of that SubRES, or in any of the scenario files.
   2a. I have started defining all commodities in SysSettings and find it more convenient for a variety of reasons.
3. I suggest you redefine your data rule as per the TOPINS logic. For example, if you want to create a UC_FLO for bio kerosene, then use regular kerosene in PSET_CI.

Processing order in Veda2.0

[james]

Thanks for the response Amit, useful information. Two more points from me:

1) To get VFE and VEDA2 to match in terms of the topologies they were producing I found:

a) for VFE I moved the TOPINS table to SysSettings (removing it from BY_Trans and SubRES_Trans), leaving the commodity definitions unchanged (so at least one of the commodities to be mapped by TOPINS was only defined in a SubRES). After a start from scratch (full resync) this seems to provide the desired topology and means the mapped TOPINS commodities are included in user constraints such as shares defined using UC_FLO.

b) for VEDA2, to match the above in terms of topology and constraints, TOPINS had to be defined in BY_Trans and SubRES_Trans. When I moved it to SysSettings (and turned it off elsewhere) it didn't work.

This difference in behaviour between VFE and VEDA2 may not matter but I thought I'd mention it. In part because it means we will need to have two different versions of the model, one for VFE and one VEDA2 (at least for the time being).

2) The user constraint I was talking about was more about UC_FLO based commodity share constraints. In those one wants to limit the flow of commodity X relative to all other inputs and that means the process topology (and TOPINS) needs to be working as expected. So I wasn't trying to create a FLO constraint for bio kerosene, more so making sure bio kerosene is included in the all other inputs sum part of the constraint. And, as described in 1a), with the latest version of VFE I found it wasn't unless I moved the TOPINS to SysSettings. I hope that makes sense.

Thanks again.

[AKanudia]

Well, I would not expect TOPINS to work in SysSettings. So Veda2 behavior seems sound to me.

What happens if you leave it in both places? Having two different versions during the migration process may be OK too.

[Antti-L]

Looking at the migration notes, I see no mention of TFM_TOPINS not working in Syssettings under VEDA2.  So, shouldn't it then work, or am I mistaken?
https://veda-documentation.readthedocs.io/en/latest/pages/Migration.html#migrating-to-veda-2-0

[AKanudia]

Apologies for the inaccurate statement. There is no specific restriction; I just meant that since SysSettings tables are processed at the very end, topology information coming from there would not be seen by UC processing.

[james]

Thanks both for the input.

Using the DemoS_007 model which is distributed with VEDA2 I've tested adding a commodity that is only defined in a SubRES and having it mapped to an existing set of process inputs via a TOPINS table which is placed in SysSettings. I then added a user constraint of the form I mentioned previously. It seems that:

1) if I first turn on the TOPINS table and sync then the process topology becomes as specified by the table but the mapped commodity is not in the user constraint.

2) if I then start from scratch the commodity becomes included in the user constraint.

So it seems there is some kind of second round of processing going on in VFE that picks up the commodity in the UC.